Key Fob Low Battery Alert Won't Reset

[boaterva]

So to close the new loop on this for my experience, did the walk in, and they fixed it in 30 minutes (probably most of that was overhead and fitting me in, if I could have put it in with a normal appointment, it's probably a better idea). He said they've been seeing more of these 'recently' and the fix is to restart something. All I caught was perhaps 'gateway' (again, that sounds like the whole car restart we've been having to have done for other things...).


And he confirmed this is why they do the battery swaps as part of the annual maintenance. Things like this.

 

[boaterva]

They also aren’t 2032 anymore, at least for the X. They are thicker ‘two tier’ looking ones. Don’t have them in front of me but bought a five pack off Amazon and the qualify seem fine. Reviews are a good way to see what you are getting and you can tell if the reviews are real by reading them.

Should be interesting what they tell me tomorrow!

It may be the X has the different batteries? I've not checked both manuals recently to compare. I know mine are the 2354 (smaller and thicker?).

 

[MyJoule]

FWIW- I just got the message to replace the battery in the key fob on our CPO car- I presume they didn't replace it when they inspected the car. Anyway- I replaced one and the message was still there even though the second key fob was out of range, So I replaced the battery own the second key fob and the message went away- Took me a bit to get the auto walk up and mirror folding to start working again though- ( seems you have to cycle them off and back on in the settings) All is now working. I did measure the voltage on both of the old batteries, both measured 2.95 volts, so they were a bit low- The new ones are 3.2V right now. Hope this is the last of this problem for a while.

 

[BigTonyTones]

FWIW- I just got the message to replace the battery in the key fob on our CPO car- I presume they didn't replace it when they inspected the car. Anyway- I replaced one and the message was still there even though the second key fob was out of range, So I replaced the battery own the second key fob and the message went away- Took me a bit to get the auto walk up and mirror folding to start working again though- ( seems you have to cycle them off and back on in the settings) All is now working. I did measure the voltage on both of the old batteries, both measured 2.95 volts, so they were a bit low- The new ones are 3.2V right now. Hope this is the last of this problem for a while.

2.95 is considered low battery in these types of devices. Same thing with wireless alarm security sensors.
3.2v is the correct voltage. You shouldn't have any issues now

 

[mkspeedr]

I have the issue on my one month old new model X. They have changed the fob battery (both) and the service center could not clear the error message.

They are sending a ranger to my house tomorrow. I worry when the service guys could not reset the error.

 

[viper2ko]

Off topic, but how long does a keyfob battery last, and what happens if I'm out and the battery dies. I can unlock the car with the app, but could I drive it?

 

[Graffi]

I was getting the error message for months on my FOB, the one my wife uses was okay. I eventually kept a spare battery in the car, just in case. I think I used the old battery almost daily for over 6 months until I finally changed it.

The point is, the warning message comes to you long before you can no longer use the FOB. If you are worried, then change it. Or, like me, if you want to get every bit of use out of it you can, then get a spare battery and keep it in the car until your FOB no longer works.

If the FOB no longer automatically unlocks the car when you walk up, I think you just hold the FOB next to the driver side door handle to open using the RFID. You can also start the car by holding the FOB next to the dash close to the steering column. You can remove your battery and try these.

In my case, when the FOB no longer opened the car I placed it next to the handle so it would unlock. Once I was in the car I swapped out the old battery with a new one I had been keeping in the car. Once the new battery was in it, the FOB worked great.

 

[jpl]

I saw this message, changed the battery in my fob, but the message persisted. I checked the battery in my wife's fob, and it was down to 80%, so I changed it. The message persisted. I popped and restored both batteries in the car. The message persisted. Both batteries test 100% (on a tester that knows about lithium button batteries.) I give up. I know my battery is fresh, and I keep a spare in the glove compartment. But Tesla is training me to ignore warning messages, and that is a very dangerous thing. Time to fix this in an over-the-air update, I think.

 

[jpl]

I saw this message, changed the battery in my fob, but the message persisted. I checked the battery in my wife's fob, and it was down to 80%, so I changed it. The message persisted. I popped and restored both batteries in the car. The message persisted. Both batteries test 100% (on a tester that knows about lithium button batteries.) I give up. I know my battery is fresh, and I keep a spare in the glove compartment. But Tesla is training me to ignore warning messages, and that is a very dangerous thing. Time to fix this in an over-the-air update, I think.

Try this [full explanation follows]:

1) After making sure all fobs have good batteries, leave a fob in the center console and exit the car for 15 minutes. (Obviously, this make your Tesla easier to steal, so do it prudently).

2) Get back in the car. I found a "FOB not in car" message, which was blatantly false. Clicking on the fob cleared that message and the low battery message.

I have no clue why this cleared the message. My wife's car battery died, so I called AAA and we met them at her car. It was pouring rain, so I left the fob in the console so my wife could get back in out of the rain if I was involved with AAA. It took at least 15 minutes for AAA to get parked near her car and do the jump. My wife was in her car, and I was standing by her car, under an umbrella, passing instructions between AAA and my wife. The jump fixed her problem, and she drove off. I got back in the car and saw the "FOB not in car" message (probably not the exact message). I clicked on the fob a few times to emphasize that it was in the car, and all warning messages went away.

I have my own doubts that this works. I picked up my wife at the airport a couple days earlier, and sat in the Tesla, which was in park, for at least 30 minutes. That sounds a lot like what happened with the battery jump. One possible difference is that I registered my presence in the car by hitting easy entry when the seat slid back. I never got a "FOB not in car" message.

 

[glangston]

Make sure both key fobs are present and both have fresh batteries.

This worked for me today (June 2022) with my 2013 Model S85. Upon replacing the battery in the second key fob (while in the car), with both key fobs present, the warning message cleared. Did not need to reboot the MCU.